Nitrofurantoin Pregnancy and Breastfeeding Warnings

Nitrofurantoin is also known as: Furadantin, Macrobid, Macrodantin, Nitro Macro

Nitrofurantoin Pregnancy Warnings

Nitrofurantoin has been assigned to pregnancy category B by the FDA. Animal studies have failed to reveal evidence of fetotoxicity or teratogenicity except when administered in very high doses. While there are no controlled data in human pregnancies, nitrofurantoin-induced congenital anomalies have not been reported to date. Nitrofurantoin should only be given during pregnancy when need has been clearly established. The use of nitrofurantoin is contraindicated near term (38 to 42 weeks gestation) and during labor and delivery because of the potential for induction of hemolytic anemia in the neonate due to low levels of red cell glutathione in this population.

One retrospective review of 91 pregnancies involving nitrofurantoin use reported no evidence of association to fetal adverse effects. In a review of 229,101 deliveries to Michigan Medicaid patients, there were 1292 first-trimester exposures to nitrofurantoin and 9998 exposures anytime during pregnancy. A total of 52 birth defects (55 expected) was reported with first-trimester exposure and included (observed/expected) 15/12 cardiovascular defects, 1/0 oral clefts, 4/3 polydactyly, 3/2 limb reductions, and 5/3 hypospadias.

Nitrofurantoin Breastfeeding Warnings

Nitrofurantoin is excreted into human milk. Nitrofurantoin is considered compatible with breast-feeding by the American Academy of Pediatrics, although there is a theoretical risk of hemolytic anemia in neonates and G-6-PD-deficient infants. The manufacturer recommends that due to the potential for serious adverse effects in infants less than one month old, a decision should be made to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

A study of 4 lactating women indicated that nitrofurantoin is actively transported into breast milk, achieving a milk-to-serum ratio of 6.21. The infant dose was estimated to be approximately 6% of the maternal dose or 0.2 mg/kg/day (based on a maternal dose of 100 mg nitrofurantoin macrocrystals twice daily).

See Also...

• Nitrofurantoin use while Breastfeeding (in more detail)
• Nitrofurantoin Consumer Information
• Pregnancy Support Group
• FDA Pregnancy Categories
• Medicine use during Pregnancy
• Medicine use while Breastfeeding
• Safe Medications during Breastfeeding

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